The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The re...The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters （such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed） was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interracial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.展开更多
The problem of adaptive radar detection in compound-Gaussian clutter without secondary data is considered in this paper.In most practical applications,the number of training data is limited.To overcome the lack of tra...The problem of adaptive radar detection in compound-Gaussian clutter without secondary data is considered in this paper.In most practical applications,the number of training data is limited.To overcome the lack of training data,an autoregressive（AR）-process-based covariance matrix estimator is proposed.Then,with the estimated covariance matrix the one-step generalized likelihood ratio test（GLRT） detector is designed without training data.Finally,detection performance of our proposed detector is assessed.展开更多
The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic lev...The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface.展开更多
基金Project(50054) supported by the Program for New Century Excellent Talents in Universityproject(20060004020) supported by the Research Fund for the Doctoral Program of Higher Education+1 种基金project(3062017) supported by the Natural Science Foundation of Beijing, Chinaproject(2004SZ007) supported by the Foundation of Beijing Jiaotong University
文摘The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interracial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters （such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed） was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interracial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.
基金supported by the Fundamental Research Funds for the Central Universities under Grant No. E022050205
文摘The problem of adaptive radar detection in compound-Gaussian clutter without secondary data is considered in this paper.In most practical applications,the number of training data is limited.To overcome the lack of training data,an autoregressive（AR）-process-based covariance matrix estimator is proposed.Then,with the estimated covariance matrix the one-step generalized likelihood ratio test（GLRT） detector is designed without training data.Finally,detection performance of our proposed detector is assessed.
基金Supported by the National Basic Research Program of China(973 Program)(Nos.2011CB409801,2014CB441502)
文摘The composition and compound-specific isotopes of fatty acids were studied within food webs in the East China Sea.Lipid-normalized stable carbon isotopes of total organic carbon had a good correlation with trophic level.Variations in fatty acid compositions among different species were observed but were unclear.Different dietary structures could be traced from molecular isotopes of selected fatty acids in the Shiba shrimp(Matapenaeus joyneri),the coastal mud shrimp(Solenocera crassicomis) and the northern Maoxia shrimp(Acetes chinensis).Both M.joyneri and S.crassicomis are mainly benthos feeders,while A.chinensis is a pelagic species,although they have a similar fatty acid composition.There was a good correlation for isotopes of arachidonic acid(C20:4n6;ARA) and docosahexaenoic acid(C22:6n3;DHA)among pelagic species from higher trophic levels.The isotopic compositions of DHA in benthic species were more negative than those of pelagic species at the same trophic level.The fact that the diet of benthic species contains more degraded items,the carbon isotopes of which are derived from a large biochemical fraction,may be the reason for this variation.A comparative study of benthic and pelagic species demonstrated the different carbon sources in potential food items and the presence of a more complex system at the watersediment interface.
